Joe Jonas is struggling with the boy band's reunion, because he can't remember all the words to their old songs.
Joe and his siblings, who reunited last year, are currently rehearsing for a major tour and the singer tells fans not to be surprised if they see him using a prompter at gigs.
"When we got the band back together, I was like, 'Guys, I haven't played this song for six or seven years,'" he tells YouTube show Hot Ones, "and Nick loves to be like, 'Let's play this one tonight'.
"I'm looking at fans' faces, like, 'Tell me the lyrics...' At that point, I was like, I'm just gonna have these prompters onstage and be shameless about it'."I don't need them for every song, but 90 per cent of the songs."